Ink jet printing apparatus comprising automatic ink jet deflection adjustment means

An ink jet printing apparatus including an ink ejection head for ejecting a jet of ink, charging means for electrostatically charging the ink jet and deflection means for electrostatically deflecting the charged ink jet, characterized by comprising:

• sweep means for causing the ink jet to sweepingly deflect along an axis;
• target electrode means disposed along said axis and having an edge intersecting said axis;
• integrating circuit means connected to the target electrode means for integrating a voltage induced on the target electrode means;
• and
• control means for controlling the sweep means to cause the ink jet to sweepingly deflect along said axis toward said edge, sensing an output voltage of the integrating circuit means, controlling the sweep means to stop sweepingly deflecting the ink jet when the output voltage of the integrating circuit means has a predetermined value indicating that the ink jet has just passed said edge and producing an electric signal having a magnitude corresponding to an amount of deflection force which the sweep means causes to be applied to the ink jet at a time the output voltage of the integrating circuit means has the predetermined value.